Solving Definite Integrals issues with SMath/Maxima

Solving Definite Integrals issues with SMath/Maxima - Solving Definite Integrals issues with SMath/Maxima - Сообщения

#1 Опубликовано: 21.07.2024 11:10:13
Lasith De Silva

Lasith De Silva

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Hello SMath Forum,

I'm a relatively new user to SMath and am still figuring out most of its functionality and quirks. For the attached worksheet I am working through three energy transfer calculations for human discharge assessments, all calculations involve solving definite integrals over a defined limit. When defining over the time period of (0,0.000001) I am getting answers magnitudes smaller than expected, the answers expected are shown below (last page of document) and the parameters/constants and base formulas used to derive the SMath worksheet are also referenced below:

Capacitive Discharge - Example Calcs.pdf (766 КиБ) скачан 40 раз(а).

The SMath working calculation sheet is here, I feel I've exhausted many different options to try and debug any issues with the calculations but I cannot find anymore alternatives:

Capacitive Discharge -TEMPLATE Case - Solve_1 - Copy.sm (48 КиБ) скачан 33 раз(а).

What's also confusing to me, when defining a longer time integral, the answer is changing? Understanding the function after the initial transient period is mostly a steady-state sinuisoidal, I expect the positive/negative peaks to be cancelling out and not contributing to the area under the curve.. Can some please assist with any functionality I have misinterpreted?

I've been advised to adopt a different engineering package like Matlab/Python (although my coding is not the strongest) and I rather enjoy the GUI of SMath - so if I can solve this quirk here I'd be happy.

Appreciate the community's help!

Cheers,

LADS
#2 Опубликовано: 21.07.2024 15:21:10
Alvaro Diaz Falconi

Alvaro Diaz Falconi

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Wrote

... The SMath working calculation sheet is here, I feel I've exhausted many different options to try and debug any issues with the calculations but I cannot find anymore alternatives. ...



Hi. The attached can help you debug your calculations.

Capacitive Discharge -TEMPLATE Case - Solve_1 - Copy.sm (100 КиБ) скачан 34 раз(а).

Wrote

... What's also confusing to me, when defining a longer time integral, the answer is changing? Understanding the function after the initial transient period is mostly a steady-state sinuisoidal, I expect the positive/negative peaks to be cancelling out and not contributing to the area under the curve.. Can some please assist with any functionality I have misinterpreted?



The steady-state solution has no limit for t -> infinity: this means, it oscillates (you can see it here, for example). It has a sup and inf limit of oscillation, then in the range of oscillation the integral can take any value between the integral range of oscillation.

Best regards.
Alvaro.
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